A hybrid power driving system employs two different power sources together, and mainly has three structures (i.e., serial connection, parallel connection, and hybrid connection) depending on the type of connection. Since the functions of the driving systems in serial or parallel connection are too simple, driving systems in hybrid connection are usually used in the prior art.
In actual applications, driving systems in hybrid connection are mainly in two types: one type employs a planetary gear unit to realize the power distribution among the power units, while the other type employs a clutch to realize the power distribution among the power units. In the former type, both the structure and the control scheme of the driving system are quite complex. In the latter type, the control is relatively complex due to the limitation in function of the clutch.
In view of the above problems, the patent applicant improved on the conventional one-way overrunning clutch that only has an overrun state and an engaged state, and thereby invented a novel tri-state overrunning clutch which not only has the overrun state and the engaged state as the conventional overrunning clutch, but also has a disengaged state.
When the tri-state overrunning clutch described above is applied in a hybrid power driving system, the structure of the hybrid power driving system can be simplified, and the control will be easier.